Canon imagePROGRAF PRO-300 13" Photographic Inkjet Printer - Manual (Page 538)

Cannot Print or Connect
Redo printer setup if one of conditions below is applied.
• if you have replaced a computer or wireless router
• if you have changed wireless router settings
• if you have changed the printer connection method (Wi-Fi/wired LAN/USB)
• if you have forgotten the administrator password specified for the printer
If you have forgotten the password, on the HOME screen, select Various settings > Printer settings >
Reset settings > Reset all to restore the password to default, and then redo printer setup.
Reset settings
Visit here for more on the setup procedure.
If none of the above is applied, see Printer Suddenly Stopped Working for Some Reason .
538